<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>includes</title>
	</head>
	<body>
		<script>
			// includes 方法用于判断一个数组中是否包含某个值
			// 若包含返回 true ，反之返回 false

			let arr = [1, 2, 300];
			let flag;
			flag = arr.includes(300);
			console.log(flag);
		</script>
	</body>
</html>
